A hedge trimmer, shrub trimmer, or bush trimmer, is a gardening tool or machine used for trimming (cutting, pruning) hedges or solitary shrubs (bushes). Different designs as well as manual and powered versions of hedge trimmers exist.

The power source of stand-alone hedge trimmers can be human power, gasoline, or electricity.

A manual hedge trimmer with telescopic handles

An electric hedge trimmer

A gasoline-powered hedge trimmer

Tractor-mounted and tractor-driven hedge trimmers also exist, but are not that common. These machines consist of a moveable arm (hydraulic boom) with a large hedge trimmer attachment at its end. Their cutting mechanism is similar to that of finger-bar mowers.

Such large hedge trimmers are often confused with tractor-mounted reach flail mowers (booms with flail mower attachments), which appear similar due to the use of booms. And in colloquial language both, tractor-mounted hedge trimmers and reach flail mowers, are called – rather imprecisely – hedge cutters, or brush cutters. In contrast to tractor-mounted hedge trimmers, reach flail mowers have a different cutting mechanism, and are not only used for trimming hedges, but also in several other fields of application (mowing taller grass, road verge cutting, ditch maintenance, etc.).